10 % of the death worldwide are associated to a traumatic injury. Stem cell based therapies are a promising approach to improve tissue repair after injury. In this project, we want to mobilize endogenous stem and progenitor cells (SPCs) to improve tissue repair. Therefore, a better understanding of SPC dynamics upon injury in mouse and human is needed. We work on establishing a mouse model for analyzing and modulating SPC dynamics upon traumatic injury. Furthermore, we examine SPC numbers in peripheral blood of polytraumatized patients. The aim of this work is to detect beneficial combinations of SPCs and to mobilize them at the ideal time point.